Search results
Results from the WOW.Com Content Network
Allopatric speciation (from Ancient Greek ἄλλος (állos) ' other ' and πατρίς (patrís) ' fatherland ') – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model [1]: 86 – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with ...
Allopatric speciation, in which two populations of the same species are geographically isolated from one another by an extrinsic barrier and evolve intrinsic (genetic) reproductive isolation. Peripatric speciation , in which a small group of a population is separated from the main body and experiences genetic drift .
In peripatric speciation, a subform of allopatric speciation, new species are formed in isolated, smaller peripheral populations that are prevented from exchanging genes with the main population. It is related to the concept of a founder effect, since small populations often undergo bottlenecks. Genetic drift is often proposed to play a ...
A classification scheme of speciation processes based on the level of gene flow between two populations. [22] The traditional terms for the three modes— allopatric , parapatric , and sympatric —are based on the spatial distributions of a species population.
Reproductive isolation can be caused by allopatric speciation. A population of Drosophila was divided into sub populations selected to adapt to different food types. After some generations the two sub populations were mixed again. Subsequent matings occurred between individuals belonging to the same adapted group. [84]
In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. [1] An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation .
The three primary geographic modes of speciation (allopatric, parapatric, and sympatric) can exist within this continuum, as well as other non-geographic modes. Because allochronic speciation can occur in conjunction with other modes and forms of speciation, researchers must attempt to determine if the initial stages of isolation were the ...
In biology, a deme, in the strict sense, is a group of individuals that belong to the same taxonomic group. [1] However, when biologists, and especially ecologists, use the term ‘deme’ they usually refer to it as the definition of a gamodeme: [2] a local group of individuals (from the same taxon) that interbreed with each other and share a gene pool. [1]